Long-Term Persistence of Bhc, DDT and Chlordane in a Sandy Loam Soil

Residues of technical BHC, DDT and chlordane present in a sandy loam soil in Nova Scotia 15 years after the last application were 7.5, 55 and 16%, respectively, of the amounts applied. BHC residues consisted of the alpha-, beta-, gamma- and delta-isomers at relative percentages of 36, 36, 16 and 12, respectively. The beta isomer was the most persistent. DDT residues consisted chiefly of p,p′-DDT, o,p′-DDT and p,p′-DDE. Residues in chlordane-treated plots were principally alpha- and gamma-chlordane. There was little downward or lateral movement of these insecticides in the soil in 15 years.